RR AE3007 engine in the Hawk is the same powerplant as the Cessna Citation X according to Wiki. The models ceiling is
given as 65000ft for the prototype. Can any engine be modified to burn JP7? I have to believe that there is
added ceiling that has not been made public (these puppies
are 25 mil+ apiece and not as expendable as Preds).
Definitely not. The J-58 engine used on the SR-71 has special inlet nozzles and compression chambers. These were built both for speed and altitude. There may be some modifications that could be made to the Global Hawk that would give it the altitude capability. It may be stealthy enough to evade the radars even at lower altitude. It certainly doesn't have the speed to outrun the missiles.